This invention discloses a wideband communications link layer interface between the digital networks employed by interexchange carriers and new wideband local loop systems connecting subscribers. For example, the invention relates to an interface for tethered radio channel (e.g., digital subscriber loops) local loops to homes and businesses that provide multiple voice and data channels over twisted pair media.
As deregulation of the telephone industry continues and as companies prepare to enter the local telephone access market, there is a need to offer new and innovative services that distinguish common carriers from their competitors. This cannot be accomplished without introducing new local access network architectures that will be able to support these new and innovative services.
Conventionally, customer premises telephone and/or data connections contain splitters for separating analog voice calls from other data services such as Ethernet transported over digital subscriber line (DSL) modems. Voice band data and voice signals are sent through a communications switch in a central or local office to an interexchange carrier or Internet service provider. DSL data is sent through a digital subscriber loop asynchronous mode (DSLAM) switch which may include a router. The DSLAM switch connects many lines and routes the digital data to a telephone company""s digital switch.
A major problem with this configuration is that interexchange carriers attempting to penetrate the local telephone company""s territory must lease trunk lines from the local telephone company switch to the interexchange company""s network for digital traffic. Furthermore, the Internet service provider must lease a modem from the local phone company in the DSLAM switch and route its data through the local phone company""s digital switch. Thus, the local phone company leases and/or provides a significant amount of equipment, driving up the cost of entry for any other company trying to provide local telephone services and making it difficult for the interexchange companies to differentiate their services. Furthermore, since DSL modem technology is not standardized, in order to ensure compatibility, the DSL modem provided by the local telephone company must also be provided to the end user in the customer premises equipment (CPE). Additionally, since the network is not completely controlled by the interexchange companies, it is difficult to for the interexchange companies to provide data at committed deliver rates. Any performance improvements implemented by the interexchange companies may not be realized by their customers, because the capabilities of the local telephone company equipment may or may not meet their performance needs. Thus, it is difficult for the interexchange companies to convince potential customers to switch to their equipment or to use their services. These factors ensure the continued market presence of the local telephone company.
As part of this system, there is a need for improved architectures, services and equipment utilized to allow the interexchange companies to offer more products and services to customers. DSL technology, one type of communication system that can use conventional twisted pair wiring, for which a large infrastructure is in place, holds the promise of providing high bandwidth communication into any telephone subscriber""s home or business. However, support for such high speed communication between the existing and future networks and the local high speed loops present major problems: For example, how can such new technology be interfaced with existing and future interexchange carrier equipment and software in a way that allows future growth? How do existing services, such as voice, facsimile, and modem communications fit into the scheme if the twisted pair formerly used for such purposes is co-opted by a new DSL-based system (for example)? How can such an interface take full advantage of the promise of wide-band connection to homes and businesses without being hamstrung by the need to interface with conventional technology? How can the huge burden of wide-band communication to subscriber""s premises be handled by interexchange carriers? For example, if people can watch movies at home, how can numerous moves be transmitted from far-flung sites without overtaxing even future interexchange carrier infrastructure?
In order to provide an improved network, it is desirable for the interexchange companies to have access to at least one of the twisted-pair lines connecting each of the individual users to the local telephone network before the lines are routed through the conventional local telephone network equipment. It is preferable to have access to these lines prior to the splitter and modem technology offered by the local service providers. By having access to the twisted-pair wires entering the customer""s premises, interexchange companies can offer better services by providing higher bandwidth, improving the capabilities of the customer premises equipment, and lowering overall system costs to the customer by enhancing competition between local exchange carriers and interexchange carriers.
The new architecture may utilize a video phone and/or other devices to provide new services to an end user, an intelligent services director (ISD) disposed near the customer""s premises for multiplexing and coordinating many digital services onto a single twisted-pair line; a facilities management platform (FMP) disposed in the local telephone network""s central office for routing data to an appropriate interexchange company network; and a network server platform (NSP) coupled to the FMP for providing new and innovative services to the customer and for distinguishing services provided by the interexchange companies from those services provided by the local telephone network.
As part of this system, one aspect of the invention provides a so-called FMP which provides a link between the local loop to the customer premises ISD (which may also be located remotely from the customer premises) and the interexchange company network.
Briefly, in summary, the FMP connects current digital and analog carrier networks and packet switched networks of interexchange carriers with high speed multiple access subscriber links implemented over twisted pair lines. The subscriber line is terminated by an access module containing one or more modems. In preferred embodiments, the modems are high-speed digital tethered virtual radio channel or xDSL modems. The interface applies and receives signaling and voice through a digital loop carrier (DLC) via a multiplexer connected directly to the DLC backplane. The multiplexer is controlled by a controller of an access module. It translates data from the subscriber link to the form compatible with the digital backplane to create the appearance of one or more line cards. The FMP also may contain a sound generator to allow it to handle calls through an analog carrier network. The FMP, through the same access module transmits data to and from the modems directly through connected digital networks, such as ATM or SONET, of an interexchange carrier. Through this interface, different network companies can offer competing products through different networks all seamlessly connected through a high speed subscriber line.
According to one embodiment, the invention is a telecommunications interface for communicating subscriber data containing voice, and signaling, and user data between (1) a digital network, (2) a digital loop carrier having an analog interface to connect telephones and a digital circuit connecting the telephone switch to other telephone switches, and (3) a subscriber link to equipment at a subscriber""s premise. The interface has a controller and a modem. The modem modulates and demodulates the subscriber data to and from the subscriber link to generate a digital stream containing the voice, and signaling, and user data. A digital filter separates the voice data from the digital stream. The controller applies the voice data to the digital circuit when the signaling data indicates the voice data is to be transmitted by the digital circuit. When the signaling data indicates the voice data is to be transmitted over the digital network, however, the controller applies the voice data to the digital network.
According to another embodiment, the invention is a central office interface between a multiple access link, established over a single twisted pair metallic interface, to a subscriber premises and a local carrier network. A digital loop carrier with a digital interface permits access to a digital backplane of the digital loop carrier. A controller with a modulator/demodulator applies voice and signaling data corresponding to multiple voice call sessions from the link to the digital interface. In the reverse direction, it also applies data corresponding to the multiple voice call sessions from the digital interface to the link.
According to still another embodiment, the invention is a method of connecting telecommunication call sessions from multiple stations at a subscriber premise, which is accomplished by generating signaling data at one of the stations and transmitting the signaling data over the multiple access link to the network interface. In response to receiving the signaling data at the network interface, the signaling data is transmitted over one of a digital loop carrier and a digital network depending on a called number in the signaling data. Then a channel is allocated in a multiple access link to a network interface to communicate data over the link, the user data corresponding to the signaling data and the channel deallocated in response to a termination of the user data.
In another embodiment, the invention provides a method of connecting telecommunication call sessions from multiple stations at a subscriber premise through a multiple access subscriber link. The following steps are performed: providing a digital interface to a backplane of a digital loop carrier, generating signaling data at a one of the stations; transmitting the signaling data over the multiple access link to the network interface; in response to receiving the signaling data at the network interface, applying the signaling data to the digital interface to create an appearance of a POT connected through a line card connected to the backplane.
In another embodiment, the invention provides a method of connecting telecommunication call sessions from multiple stations at a subscriber premise through a multiple access subscriber link. The method includes the following steps: providing a digital interface to a backplane of a digital loop carrier; generating signaling data at a one of the stations; transmitting the signaling data over the multiple access link to the network interface; generating DTMF tones and applying the tones to a telecommunications switch responsively to the signaling data and then subsequently connecting a call initiated at the one of the stations through a channel opened up in the step of applying the tones; generating further signaling data at another one of the stations transmitting the further signaling data over the multiple access link to the network interface; setting up a call session for transmission through a virtual channel of a digital network connected to the network interface (the step of setting up a call including transmitting a request on a signaling channel of the digital network for bandwidth required for a call corresponding to the signaling data); and applying subsequent voice data in a virtual channel responsively to a result of the step of transmitting a request.
According to still another embodiment, the invention provides a method of connecting telecommunication call sessions from multiple stations at a subscriber premise through a multiple access subscriber link. The following steps are included in the method. An indication of an initiation of a voice-dialing call at one of the stations is generated (for example, a phone is picked up for a period of time without dialing). This indication is transmitted through the link to network interface and, upon receipt of the indication at the network interface, a channel is opened in a digital network. Voice data corresponding to the called number are transmitted through the channel to a server of the network. The server determines the called number and sends it to the network interface. The network interface then connects a call based on the signaling data.